Risk Factors For Renal Function Impairment Following Radiofrequency Ablation Of Renal Tumors Ⅱ

STATISTICAL ANALYSIS 

Group comparisons were performed using univariable and multivariable logistic regression analysis to evaluate the risk factors for renal function impairment after RFA. A paired t-test was used to compare the SCr level and eGFRs evaluated pre-RFA and upon 1-year follow-up. Differences in repeatedly recorded SCr levels and eGFRs were evaluated using repeated-measures ANOVA. When Mauchly's sphericity assumptions were not met (p < 0.05), either Greenhouse-Geisser (ε < 0.75) or Huynh-Feldt (ε ≥ 0.75) corrections were performed to rectify the ANOVA F statistic for main and interaction effects. All statistical analyses were performed using SPSS version 26.0 (IBM Corp., Armonk, NY, USA). A p-value < 0.05 was considered statistically significant.

ORGANIC HERB CISTANCHE FOR KIDNEY DISEASE

RESULTS

Residual tumors were detected in 9 of the 91 patients on the first follow-up CT images; hence the technical efficacy rate was 90.1% (82/91). Among the nine tumors, eight additional RFAs were performed successfully for eight; one rejected the additional RFA. Local tumor progression was found in 12 of the 91 patients (local tumor progression rate: 13.2%) at various follow-up intervals within 5 years after RFA procedures. Eight patients with local tumor progression were treated with repeated RFA. Of these, one patient experienced recurrence since the second procedure. The patient underwent subsequent RFA and no sign of recurrence was observed for 12 months since the last RFA. Two patients having local tumor progression refused further treatment. One patient was diagnosed with biopsy-proven oncocytoma, and the other showed lung and bone metastases 16 months after RFA and was treated with chemotherapy and radiotherapy.

The overall complication rate in the 108 RFA sessions was 29.6% (32/108). Most of the complications (30/32; 93.8%) were minor, including 24 perinephric or subcapsular hematomas, and 6 mild hydronephrosis due to pyeloureteral injuries. All hematoma cases were managed with supportive care and resolved within 3 months. Two major complications occurred (2/32; 6.3%), which were pyeloureteral injuries that required percutaneous nephrostomy and insertion of a double J ureteral catheter, respectively, and resulted in a ureteropelvic junction stricture (Fig. 1). Tables 3 and 4 show the variables significantly associated with renal function impairment 

Fig. 1. A 67-year-old male with an injury at the ureteropelvic junction. A. Pre-RFA kidney CT image during the corticomedullary phase shows a 1-cm endophytic renal tumor (arrow) in the medial portion of the right kidney lower pole and close proximity to the upper ureter (arrowhead). Pre-RFA SCr and eGFR were 0.73 mg/dL and 115 mL/min/1.73 m2, respectively. B. CT-guided RFA was done with the patient in the left lateral decubitus position on the CT table. RF electrode (arrow) abuts on the upper ureter (arrowhead). C. The next-day post-RFA kidney CT image shows complete ablation of the renal tumor (arrow), but enhancing wall thickening of the ureteropelvic junction is newly detected (arrowhead). D. Four-month post-RFA kidney CT image shows ureteropelvic junction stricture (arrowhead) and hydronephrosis. Abscess pockets and inflammatory thickening (arrow) are detected at the right perinephric space. Post-RFA SCr increased to 1.24 mg/dL and eGFR decreased to 69.2 mL/min/1.73 m2, respectively. eGFR = estimated glomerular filtration rates, RFA = radiofrequency ablation, SCr = serum creatinine upon univariable and multivariable logistic regression analysis. In univariable analysis, age, solitary kidney, CKD stage 3, R.E.N.A.L score, and pyeloureteral injury were found to be significantly associated (p < 0.05). Among these, solitary kidney [odds ratio (OR) = 176.723, p = 0.026], CKD stage 3 (OR = 43.583, p = 0.024), and pyeloureteral injury (OR = 36.848, p = 0.043) remained significantly associated (p < 0.05) upon multivariable analysis. The R.E.N.A.L. score (OR = 5.872, p = 0.071) and age (OR = 1.56, p = 0.086), followed a trend toward significance. Other variables such as sex, other previously diagnosed cancers, tumor size, location, growth pattern, nearness to the collecting system, and pathologic types were not positively associated with decreased renal function (p > 0.1).

Renal function test results regarding SCr levels and eGFRs at pre-RFA were significantly different from those obtained at the 1-year follow-up. The mean pre-RFA SCr level was 1.11 mg/dL, which significantly increased to 1.57 mg/dL at the 1-year follow-up (p < 0.0001) in group A (Table 5). The mean pre-RFA eGFR was 72.2 mL/min/1.73 m2, which significantly decreased to 43.3 mL/min/1.73 m2 (p < 0.0001) in group A (Table 5). Group B showed insignificant changes in renal function tests before and after RFA (Table 5).

A repeated-measures ANOVA measured at preset times (pre-RFA and post-RFA at 1 day, 3 days, 1 week, 1 month, 6 months, and 1 year) was used to evaluate any interaction between the risk factors (solitary kidney, CKD stage 3, and pyeloureteral injury) and renal function impairment (Fig. 2). Within-patient main effects between the predetermined times were significant for solitary kidney (SCr: F = 9.005, p < 0.0001, eGFR: F = 5.573, p < 0.0001), CKD stage 3 (SCr: F = 10.031, p < 0.0001, eGFR: F = 1.924, p = 0.046), and pyeloureteral injury (SCr: F = 4.969, p < 0.0001, eGFR: F = 2.533, p = 0.027). Thus, SCr and eGFR showed statistically significant changes with time. Significant within-patient differences in interactions between the risk factors (solitary kidney, CKD stage 3, and pyeloureteral injury) and decreased renal function outcome were detected for the solitary kidney (SCr: F = 3.522, p = 0.004, eGFR: F = 2.611, p = 0.023), CKD stage 3 (SCr: F = 6.053, p < 0.0001, eGFR: F = 1.545, p = 0.043), and pyeloureteral injury (SCr: F = 3.376, p = 0.005, eGFR: F = 1.866, p = 0.024). There was a difference in overall change over time between the variables: with- and without solitary kidney, CKD stage 3, and pyeloureteral injury

Table 4. Multivariable Analysis of Renal Function Impairment (Impaired = Group A, Unimpaired = Group B)